In recent years, the number of vehicles with an automatic engine stop and start system (it's also so called as an idle stop system) is increasing. The system stops an internal combustion engine automatically to carry out an idle stop when an automobile is stopped and restarts the engine automatically when the automobile is restarted from the idle stop, in order to reduce exhaust gases of vehicles. In a vehicle with the idle stop function, the starter needs to be driven each time the engine is restarted. The starter needs to restart the engine with the following action: when passing current to a magnetic switch for connecting electrically a starter motor and a battery, a pinion is moved toward a ring gear of the engine by the driving force of the electromagnetic switch (actuator); thereby the starter motor is connected to the battery and rotates so that the pinion meshes with the ring gear; and torque of the starter motor is transmitted to a crankshaft of the engine through the pinion gear and ring gear. Consequently, the automatic engine stop and start system has a problem that it takes long time to restart the engine and the vehicle cannot move promptly. Particularly, when the pinion and the ring gear collide with each other before meshing, it takes longer time to restart the engine.
To solve such a problem, a technique described in the patent document 1 (Japanese Patent Laid-open No. 2000-45920) is provided. According to the technique, it makes possible to shorten time to restart the engine by driving a magnetic switch during an automatic engine stop (idle stop mode) and holding a plunger of the magnetic switch with a plunger stopper so as to keep a state of a pinion meshing with a ring gear.
However, in the technique, since the plunger stopper uses a solenoid only for holding the plunger of the magnetic switch, the technique has a problem of low mountability.
An object of the present invention is to provide a starter capable of keeping a state where a pinion and a ring gear remain meshing with each other when an engine automatically is stopped, without a plunger stopper having a solenoid.